Conventionally, a display unit (or a display) for use in automobiles is typically built in an instrument panel or fixed to a cabin ceiling. Displays have been becoming multifunctional and vehicle-mounted display apparatus can offer different types of information, such as DVD reproduced information, TV programs, as well as road guidance information provided by a navigation system, using an identical display.
A display unit which is originally provided as a display of a navigation system and is built in and fixed to, for example, an instrument panel of a motor vehicle so that the display unit is suitable for visual observation from a driver's seat has an attitude which is not suitable for the visual observation of a passenger in a back seat of the motor vehicle who is watching a DVD reproduced image or a TV program, and becomes an obstacle of the driver of the motor vehicle because such an image which can interfere with the driver's concentration may go into the field of view of the driver. On the other hand, when the driver takes a reclining state when he or she is stopping the motor vehicle, he or she cannot enjoy image information displayed on the display unit since the orientation of the driver's face is different from that at the time of the operation of the motor vehicle.
In order to meet user demands to want to watch a DVD reproduced image or a TV program while he or she is lying on his or her back on a flat backseat, an additional display unit must be newly disposed on the cabin ceiling. However, since the frequency in use of such a display unit intended for backseats is generally low and the addition of a display unit intended for backseats provides an extra cost, it is rare to install an additional display unit for backseats and it is therefore difficult to provide passengers in backseats with satisfaction in most cases.
On the other hand, as a technology for changing the attitude of a display unit in a cabin, “A vehicle-mounted display including a display device and a supporting member attached to a wall surface on a side of a seat of a vehicle, for supporting the display device, wherein a guiding mechanism for guiding the display device from a standby state in which the screen of the display device is parallel to the wall surface to a display viewing state in which the display device stands from the wall surface toward the inner side of the cabin, and the screen of the display unit is oriented toward the seat is disposed between the display device and the supporting member” is disclosed (for example, refer to patent reference 1). As another technology for changing the attitude of a display unit in a cabin, “A thin display unit which is, as a storing means disposed in a vehicle seat, mounted to a disk player so that the display unit can move in parallel” is disclosed (for example, refer to patent reference 2).
However, either of the technologies disclosed by the above-mentioned patent references simply moves the display device or display unit in a small range which is allowed by the guiding mechanism so as to change the attitude of the display device or display unit, and is not intended for a large positional displacement of the display device or display unit from a fixed position within a built-in instrument panel to a position on the cabin's ceiling so as to solve the above-mentioned problem, for example. In addition, since the related art technologies do not have a technical idea of mounting and demounting a cabinet (which accommodates a display unit therein) to and from a supporting member, the related art technologies do not make it possible for the single display unit to be used at different positions.    Patent reference 1: JP,7-309179,A    Patent reference 2: JP,7-23311,A
A problem with a related art vehicle-mounted display apparatus which is so constructed as mentioned above is that while it can change the attitude of a display unit, it cannot allow users to use the display unit at different times and at different positions with a simple operation since it does not have a means for easily mounting and demounting the display unit to and from a supporting base.
The present invention is made in order to solve the above-mentioned problems, and it is therefore an object of the present invention to a vehicle-mounted display apparatus which can allow users to use the display unit at different times and at different positions with a simple operation.